Results, Scenario 1: Door Open + Box Fan Exhaust + Circulating Box Fan

Conditions:

Dry ice was used to raise CO₂ levels in the QLFC conference room. When CO₂ reached greater than 2,000 ppm, the dry ice was removed from the room and a box fan was placed in a door open to outside air. The time for the CO₂ to reach approximately 37% of the peak level was measured.

Outside CO₂ level = 415 ppm. Peak CO₂ = 2,418 ppm. With the open door and exhaust fan, the time for the CO₂ level to drop to <37% peak (1,045 ppm) was 7 minutes 22 seconds = 0.123 hours.

Result:

With an open door and exhaust fan, CO₂ level dropped from a peak level of 2,418 ppm to 1,045 ppm in 7 minutes 22 seconds. The calculated result indicated that 9.4 ACH was achieved under these conditions, which exceeded the target of 4 to 5 ACH. This example shows that by simply opening a door and using an exhaust fan, the outside air exchange can be increased significantly.